Hi everyone, hoping for some assistance with a PA issue that has me confused.
I am looking at a PA system in a building which consists on a 240W Amp (100v line out) and several speakers and horns totalling approximately 200W load.
The problem is if I tap a cabinet speaker to 5W and it is next to a horn tapped to 30W the audio out is the same (or very similar).
I have worked on similar PA Systems and note an obvious difference when this is done but on this particular system it seems that regardless of speaker or horn and tapping (always at 100V) the level of every single speaker is the same.
The system comprises of the following:
TOA 2240 amp
TOA SC630 horns
TOA F2322 ceiling speakers
TOA BS1030 cabinet speakers
Any advise or assistance would be greatly appreciated.
I am looking at a PA system in a building which consists on a 240W Amp (100v line out) and several speakers and horns totalling approximately 200W load.
The problem is if I tap a cabinet speaker to 5W and it is next to a horn tapped to 30W the audio out is the same (or very similar).
I have worked on similar PA Systems and note an obvious difference when this is done but on this particular system it seems that regardless of speaker or horn and tapping (always at 100V) the level of every single speaker is the same.
The system comprises of the following:
TOA 2240 amp
TOA SC630 horns
TOA F2322 ceiling speakers
TOA BS1030 cabinet speakers
Any advise or assistance would be greatly appreciated.
Check that the different transformer taps are actually providing different sound output levels.
So play some constant level music, even better pink noise, connect *one* speaker to 100V out and try all taps one by one.
It *must* sound louder on the 30W one, progressively weaker on then others and weakest on the 5W one.
Do it on all suspect speakers.
Some PA speakers allow either transformer input or direct to speaker voice coil, 0ften by adding or removing some short link or using different terminals, maybe your transformers are not in circuit at all.
So play some constant level music, even better pink noise, connect *one* speaker to 100V out and try all taps one by one.
It *must* sound louder on the 30W one, progressively weaker on then others and weakest on the 5W one.
Do it on all suspect speakers.
Some PA speakers allow either transformer input or direct to speaker voice coil, 0ften by adding or removing some short link or using different terminals, maybe your transformers are not in circuit at all.
I don't have site access at the moment however I can confirm several speakers were tested individually on a different Amp and adjusting the tapping made distinct differences in the audio levels as you would expect.
There are currently 24 speakers with various tapings connected to the AMP.
I am wondering if the AMP could be at fault. What would the effects be if the AMP line out voltage was significantly lower than 100V.
Also the cabling between speakers is not double insulated and the conductor is thin, maybe 1.5mm.
Being 100V line out I would use double insulated 2.5mm as a minimum. Could the small conductor cause significant voltage drop and what would be overall effects be?
If the AMP master volume is turned up further than required could this mask the issue where tapings seem to make no difference?
Sorry I cannot be on site atm to continue testing and provide updates.
There are currently 24 speakers with various tapings connected to the AMP.
I am wondering if the AMP could be at fault. What would the effects be if the AMP line out voltage was significantly lower than 100V.
Also the cabling between speakers is not double insulated and the conductor is thin, maybe 1.5mm.
Being 100V line out I would use double insulated 2.5mm as a minimum. Could the small conductor cause significant voltage drop and what would be overall effects be?
If the AMP master volume is turned up further than required could this mask the issue where tapings seem to make no difference?
Sorry I cannot be on site atm to continue testing and provide updates.
1)
:
2)
Both statements do not match.
3) I suggest:
Go back to that particular pair, confirm each of them has adjustable volume by tap selection, then set speaker to 30 and horn to 5, speaker must be louder than horn; then speaker to 5, horn to 30, the horn should be louder than speaker.
No need for further testing until this paradox is solved.
But in another post you confirm this is NOT the case
:2)
So which one is true?
Both statements do not match.
3) I suggest:
Go back to that particular pair, confirm each of them has adjustable volume by tap selection, then set speaker to 30 and horn to 5, speaker must be louder than horn; then speaker to 5, horn to 30, the horn should be louder than speaker.
No need for further testing until this paradox is solved.
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Sorry it is difficult to explain what has happened to date so in brief a fault was logged for low level audio on two speakers in one particular room. These are FC2322 Toa Ceiling speakers 100 V line: 330 Ω (30 W), 1 kΩ (10 W), 3.3 kΩ (3 W), 10 kΩ (1 W). Advised tech to increase the tapping from current 3W to 30W, told this made no difference. Sent a TOA BS1030 & Toa SC630m to site from my test kit which are regularly adjusted for testing the dB variations when changing the taping on my audio level meter, also measuring the impedance variation for each taping so I know these speakers work fine. The BS1030 was added to the room in question and set to 30W. Tech advised the sound level was the same as the original speakers. Further investigation highlighted that all speakers within the building (24 in total) with tapings varying from 3 to 30W output approximately the same level. I am trying to understand what would cause an equalisation of the impedance of all speakers regardless of transformer tapings or another reason for all speakers to level off at the same output. Speakers are wired in parallel btw. I am going to ship another AMP however only because I am out of ideas other than wiring the entire building properly with the correct cable and in short runs of 4-5 speakers in parallel and all runs consolidated just prior to the 100V line output of the AMP. This is how I normally have PA Systems installed regardless of zoning so faults can quickly be narrowed down to one run and then drill down on the faulty speaker, wiring etc. Again appreciate you advice and any hints on things to try.
In principle I don´t trust your Tech.
Different suggestions:
1) if at all possible, go check it yourself.
2) if too far away, reduce test to the simplest possible, to minimize doubts, misunderstandings, etc. and let´s try to put subjective evaluations out of the picture.
a) To momentarily discard building size wiring (which can be a can of worms) have Tech play pink noise (to put Music type and random level variations out of the picture) at a given level which he will NOT readjust during the test, and connect one of your test speakers straight at amp 100V line output, with a short (a couple meters) cable, and no other load connected.
Then vary speaker setting from 3W to 30 W ... it MUST change level, period.
b) Then replace test speaker by the second one you sent, it also MUST change level according to tap.
c) now you confirmed Physics Laws still hold true, bring the two suspect speakers, repeat this basic simple test.
Do NOT readjust level, if anything mute amp or turn it off while he goes pick the doubtful speakers.
Doubtful speakers either work properly , meaning volume changes significantly according to tap selected, or they don´t, in which case there is some internal problem.
Or your Tech has no clue and he´s changing taps wrong, but this would have been detected by fresh test speakers "not changing" either.
d) absolute worst case, connect with him realtime, say by Skype or Whatsapp , and have him show you the "impossible problem" before your very eyes.
FWIW I often have to write "NFF" (no fault found) and "OE" (operator error) on repair bills, go figure.
Ok, do the testing, in any case a lot of time and $$$ saved compared to tearing down all wiring and starting from zero.
Of course, maybe in the end you have to rewire, but let´s check first it´s actually needed.
Good luck.
Different suggestions:
1) if at all possible, go check it yourself.
2) if too far away, reduce test to the simplest possible, to minimize doubts, misunderstandings, etc. and let´s try to put subjective evaluations out of the picture.
a) To momentarily discard building size wiring (which can be a can of worms) have Tech play pink noise (to put Music type and random level variations out of the picture) at a given level which he will NOT readjust during the test, and connect one of your test speakers straight at amp 100V line output, with a short (a couple meters) cable, and no other load connected.
Then vary speaker setting from 3W to 30 W ... it MUST change level, period.
b) Then replace test speaker by the second one you sent, it also MUST change level according to tap.
c) now you confirmed Physics Laws still hold true, bring the two suspect speakers, repeat this basic simple test.
Do NOT readjust level, if anything mute amp or turn it off while he goes pick the doubtful speakers.
Doubtful speakers either work properly , meaning volume changes significantly according to tap selected, or they don´t, in which case there is some internal problem.
Or your Tech has no clue and he´s changing taps wrong, but this would have been detected by fresh test speakers "not changing" either.
d) absolute worst case, connect with him realtime, say by Skype or Whatsapp , and have him show you the "impossible problem" before your very eyes.
FWIW I often have to write "NFF" (no fault found) and "OE" (operator error) on repair bills, go figure.
Ok, do the testing, in any case a lot of time and $$$ saved compared to tearing down all wiring and starting from zero.
Of course, maybe in the end you have to rewire, but let´s check first it´s actually needed.
Good luck.
If I could get to site I think the mystery would be solved however I am in Australia and nothing is close here. The site is over 3300kms away as the crow flies so a site visit any time soon is out of the question.
I am putting a concise test plan together for the tech when he next attends in a couple of week (he is only 100kms away from the site) and will include your ideas as well as my own.
I will get back with an update eventually, thanks for the support to date.
I am putting a concise test plan together for the tech when he next attends in a couple of week (he is only 100kms away from the site) and will include your ideas as well as my own.
I will get back with an update eventually, thanks for the support to date.
I was called, a few years ago, to a similar situation. The "fault" I traced to two speakers wired in series, not parallel with the line supply. That caused the speakers to be governed by the lowest wattage value setting. This was after some redecoration was carried out in the office in question.
If in doubt, do it yourself!
If in doubt, do it yourself!
Oh, Argentina is also large, 3700km North to South and that just in the Continental section, that´s why I am incredibly annoying writing questions which must be answered with numbers, or yes/no ; precisely to make "remote control" possible .... "as if I were there".
Remember I told you "I don´trust your Tech"
.... many times have wasted time and energy trying to reconcile contradicting or very vague data.- Status
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